JP7477999B2 - Activated carbon and method for suppressing moldy odor using the same - Google Patents
Activated carbon and method for suppressing moldy odor using the same Download PDFInfo
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- JP7477999B2 JP7477999B2 JP2020046330A JP2020046330A JP7477999B2 JP 7477999 B2 JP7477999 B2 JP 7477999B2 JP 2020046330 A JP2020046330 A JP 2020046330A JP 2020046330 A JP2020046330 A JP 2020046330A JP 7477999 B2 JP7477999 B2 JP 7477999B2
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims description 256
- 238000000034 method Methods 0.000 title claims description 45
- 239000011148 porous material Substances 0.000 claims description 83
- 238000001179 sorption measurement Methods 0.000 claims description 65
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 38
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 35
- 239000002245 particle Substances 0.000 claims description 31
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 22
- 239000001569 carbon dioxide Substances 0.000 claims description 19
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 19
- 238000004458 analytical method Methods 0.000 claims description 14
- 229910052757 nitrogen Inorganic materials 0.000 claims description 11
- 239000007788 liquid Substances 0.000 claims description 6
- 238000004438 BET method Methods 0.000 claims description 5
- 238000001994 activation Methods 0.000 description 29
- 238000003775 Density Functional Theory Methods 0.000 description 28
- 239000000126 substance Substances 0.000 description 27
- 230000004913 activation Effects 0.000 description 26
- 239000004021 humic acid Substances 0.000 description 26
- 239000003575 carbonaceous material Substances 0.000 description 25
- QJZYHAIUNVAGQP-UHFFFAOYSA-N 3-nitrobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid Chemical compound C1C2C=CC1C(C(=O)O)C2(C(O)=O)[N+]([O-])=O QJZYHAIUNVAGQP-UHFFFAOYSA-N 0.000 description 22
- 238000005259 measurement Methods 0.000 description 17
- 235000013162 Cocos nucifera Nutrition 0.000 description 12
- 244000060011 Cocos nucifera Species 0.000 description 12
- 235000019645 odor Nutrition 0.000 description 12
- 238000000746 purification Methods 0.000 description 11
- 239000007789 gas Substances 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 10
- 230000000704 physical effect Effects 0.000 description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000003610 charcoal Substances 0.000 description 9
- 239000002994 raw material Substances 0.000 description 9
- 239000000243 solution Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 241000196324 Embryophyta Species 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 239000000843 powder Substances 0.000 description 6
- 238000009826 distribution Methods 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 5
- 239000012535 impurity Substances 0.000 description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 description 5
- 239000011707 mineral Substances 0.000 description 5
- 235000010755 mineral Nutrition 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 239000003153 chemical reaction reagent Substances 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 239000011630 iodine Substances 0.000 description 4
- 229910052740 iodine Inorganic materials 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 239000003463 adsorbent Substances 0.000 description 3
- 239000011259 mixed solution Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 239000011550 stock solution Substances 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000002834 transmittance Methods 0.000 description 3
- 239000002023 wood Substances 0.000 description 3
- LFYXNXGVLGKVCJ-FBIMIBRVSA-N 2-methylisoborneol Chemical compound C1C[C@@]2(C)[C@](C)(O)C[C@@H]1C2(C)C LFYXNXGVLGKVCJ-FBIMIBRVSA-N 0.000 description 2
- LFYXNXGVLGKVCJ-UHFFFAOYSA-N 2-methylisoborneol Natural products C1CC2(C)C(C)(O)CC1C2(C)C LFYXNXGVLGKVCJ-UHFFFAOYSA-N 0.000 description 2
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000003763 carbonization Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000015271 coagulation Effects 0.000 description 2
- 238000005345 coagulation Methods 0.000 description 2
- 230000001186 cumulative effect Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- DTGKSKDOIYIVQL-UHFFFAOYSA-N dl-isoborneol Natural products C1CC2(C)C(O)CC1C2(C)C DTGKSKDOIYIVQL-UHFFFAOYSA-N 0.000 description 2
- 235000013399 edible fruits Nutrition 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000003077 lignite Substances 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- -1 sawdust Substances 0.000 description 2
- 238000004062 sedimentation Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000012086 standard solution Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 229920003002 synthetic resin Polymers 0.000 description 2
- 239000000057 synthetic resin Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- JLPUXFOGCDVKGO-TUAOUCFPSA-N (-)-geosmin Chemical compound C1CCC[C@]2(O)[C@@H](C)CCC[C@]21C JLPUXFOGCDVKGO-TUAOUCFPSA-N 0.000 description 1
- 239000001075 (4R,4aR,8aS)-4,8a-dimethyl-1,2,3,4,5,6,7,8-octahydronaphthalen-4a-ol Substances 0.000 description 1
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 1
- PUKLDDOGISCFCP-JSQCKWNTSA-N 21-Deoxycortisone Chemical compound C1CC2=CC(=O)CC[C@]2(C)[C@@H]2[C@@H]1[C@@H]1CC[C@@](C(=O)C)(O)[C@@]1(C)CC2=O PUKLDDOGISCFCP-JSQCKWNTSA-N 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- FCYKAQOGGFGCMD-UHFFFAOYSA-N Fulvic acid Natural products O1C2=CC(O)=C(O)C(C(O)=O)=C2C(=O)C2=C1CC(C)(O)OC2 FCYKAQOGGFGCMD-UHFFFAOYSA-N 0.000 description 1
- 240000007049 Juglans regia Species 0.000 description 1
- 235000009496 Juglans regia Nutrition 0.000 description 1
- 229920001328 Polyvinylidene chloride Polymers 0.000 description 1
- 229920000297 Rayon Polymers 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- 239000012190 activator Substances 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 1
- 239000003830 anthracite Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000002802 bituminous coal Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 239000011300 coal pitch Substances 0.000 description 1
- 239000011280 coal tar Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- DTPCFIHYWYONMD-UHFFFAOYSA-N decaethylene glycol Polymers OCCOCCOCCOCCOCCOCCOCCOCCOCCOCCO DTPCFIHYWYONMD-UHFFFAOYSA-N 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- JLPUXFOGCDVKGO-UHFFFAOYSA-N dl-geosmin Natural products C1CCCC2(O)C(C)CCCC21C JLPUXFOGCDVKGO-UHFFFAOYSA-N 0.000 description 1
- 239000003651 drinking water Substances 0.000 description 1
- 235000020188 drinking water Nutrition 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000002509 fulvic acid Substances 0.000 description 1
- 229940095100 fulvic acid Drugs 0.000 description 1
- 229930001467 geosmin Natural products 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 238000011086 high cleaning Methods 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 150000002605 large molecules Chemical class 0.000 description 1
- 238000007561 laser diffraction method Methods 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 235000013379 molasses Nutrition 0.000 description 1
- ZPIRTVJRHUMMOI-UHFFFAOYSA-N octoxybenzene Chemical compound CCCCCCCCOC1=CC=CC=C1 ZPIRTVJRHUMMOI-UHFFFAOYSA-N 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 239000003415 peat Substances 0.000 description 1
- 238000004525 petroleum distillation Methods 0.000 description 1
- 239000011301 petroleum pitch Substances 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 239000008055 phosphate buffer solution Substances 0.000 description 1
- 239000005033 polyvinylidene chloride Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000011085 pressure filtration Methods 0.000 description 1
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- 238000011160 research Methods 0.000 description 1
- 238000000790 scattering method Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000006228 supernatant Substances 0.000 description 1
- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 235000020234 walnut Nutrition 0.000 description 1
- 239000002759 woven fabric Substances 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/40—Capture or disposal of greenhouse gases of CO2
Landscapes
- Water Treatment By Sorption (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Carbon And Carbon Compounds (AREA)
Description
本発明は、浄水処理用途に有用な活性炭およびそれを用いてカビ臭を抑制する方法に関する。 The present invention relates to activated carbon useful for water purification applications and a method for suppressing mold odors using the same.
原水の浄水処理施設では、原水中における不純物質を除去するために、活性炭（特に粉末活性炭）が吸着剤として使用されている。このような不純物としては、例えば、ジェオスミンや２－メチルイソボルネオール（以下、単に「２－ＭＩＢ」とも称する）のようなカビ臭原因物質、クロロホルム、トリハロメタン前駆体物質等を挙げることができる。活性炭によるこれらの不純物質の吸着性能を向上させるために、細孔容積や比表面積等の表面構造を規定した活性炭が提案されている（例えば、特許文献１～特許文献３参照）。 In raw water purification facilities, activated carbon (particularly powdered activated carbon) is used as an adsorbent to remove impurities from raw water. Examples of such impurities include substances that cause moldy odors, such as geosmin and 2-methylisoborneol (hereinafter also simply referred to as "2-MIB"), chloroform, trihalomethane precursors, etc. In order to improve the adsorption performance of activated carbon for these impurities, activated carbon with a specified surface structure, such as pore volume and specific surface area, has been proposed (see, for example, Patent Documents 1 to 3).
一方、近年、原水中における２－ＭＩＢの濃度が夏季に顕著に上昇する傾向が見られている。そのため、カビ臭抑制の対策として、２－ＭＩＢの吸着性能を向上させた活性炭が着目されている。例えば、特許文献１には、直径１．８ｎｍ以下の細孔容積を０．２８ｍｌ／ｇ以上、かつメジアン径を３０μｍ以下に規定した粉末活性炭が、２－ＭＩＢ等のカビ臭成分の除去性能を向上できることが記載されている。 On the other hand, in recent years, the concentration of 2-MIB in raw water has tended to rise significantly in the summer. For this reason, activated carbon with improved 2-MIB adsorption performance has been attracting attention as a measure to suppress moldy odors. For example, Patent Document 1 describes that powdered activated carbon with a pore volume of 0.28 ml/g or more for pores with diameters of 1.8 nm or less and a median diameter of 30 μm or less can improve the removal performance of moldy odor components such as 2-MIB.
浄水処理される原水には、通常、フミン酸やフルボ酸等のフミン質（腐植物質）が混入している。フミン質は、植物が細菌やバクテリア等の微生物によって分解された結果物であり、酸性の無定形高分子有機物である。一般的に、浄水処理施設では、原水中にフミン質と２－ＭＩＢ等のかび臭原因物質とが共に存在している状態（以下、単に「フミン質共存下」とも称する）で、活性炭を投入または供給等を行うことにより２－ＭＩＢ等のかび臭原因物質が吸着および除去される。２－ＭＩＢと比較して大きい分子であるフミン質は、その後、凝集沈殿法または急速濾過法等により除去されることが多い。しかしながら、このような浄水処理工程によると、活性炭により２－ＭＩＢが吸着される際にフミン質も活性炭に吸着されてしまうため、２－ＭＩＢが良好に吸着されていないということが考えられる。 Raw water to be purified usually contains humic substances (humic substances) such as humic acid and fulvic acid. Humic substances are the result of decomposition of plants by microorganisms such as bacteria, and are acidic amorphous polymeric organic matter. Generally, in water purification facilities, activated carbon is added or supplied to raw water in a state where humic substances and musty odor-causing substances such as 2-MIB are present together (hereinafter simply referred to as "humic substance coexistence"), and musty odor-causing substances such as 2-MIB are adsorbed and removed. Humic substances, which are larger molecules than 2-MIB, are often then removed by coagulation sedimentation or rapid filtration. However, in such water purification processes, when 2-MIB is adsorbed by activated carbon, humic substances are also adsorbed by activated carbon, so it is thought that 2-MIB is not well adsorbed.
前述した特許文献１には、細孔容積とメジアン径だけでなく、さらには比表面積を７００～２０００ｍ２／ｇに規定した粉末活性炭についても記載されている。しかしながら、これらの粉末活性炭の細孔容積、メジアン径および比表面積の数値は、２－ＭＩＢの存在のみを考慮して、その吸着性能から規定されたものである。従って、たとえこのような粉末活性炭を用いた場合でも、前述したような実際の浄水処理施設での処理工程において、２－ＭＩＢを良好に吸着できているとは限らない。 The aforementioned Patent Document 1 also describes powdered activated carbon with a pore volume and median diameter, as well as a specific surface area of 700 to 2000 m2 /g. However, the pore volume, median diameter, and specific surface area of these powdered activated carbons are specified from the adsorption performance, taking into account only the presence of 2-MIB. Therefore, even if such powdered activated carbon is used, it is not necessarily the case that 2-MIB can be well adsorbed in the treatment process at an actual water purification facility as described above.
そこで、本発明は、フミン質共存下においても２－ＭＩＢを良好に吸着することができる活性炭を提供することを目的とする。 The present invention aims to provide activated carbon that can effectively adsorb 2-MIB even in the presence of humic substances.
本発明者らは、上記課題を解決すべく鋭意検討を行った結果、本発明に到達した。すなわち本発明は、以下の好適な態様を包含する。 The inventors conducted extensive research to solve the above problems and arrived at the present invention. That is, the present invention includes the following preferred aspects.
本発明の一局面に係る活性炭は、窒素吸着等温線からＢＪＨ法で算出される細孔容積（Ａ）に対する、二酸化炭素吸着等温線からＤＦＴ解析で算出される総細孔容積（Ｂ）の比率（Ｂ）／（Ａ）が、１．６以上７．０以下である。 In one aspect of the present invention, the activated carbon has a ratio (B)/(A) of the total pore volume (B) calculated from the carbon dioxide adsorption isotherm by DFT analysis to the pore volume (A) calculated from the nitrogen adsorption isotherm by the BJH method, which is 1.6 or more and 7.0 or less.
前述の活性炭は、二酸化炭素吸着等温線からＢＥＴ法で算出される比表面積（Ｃ）が、８６０ｍ２／ｇ以上１５００ｍ２／ｇ以下であると好ましい。 The above-mentioned activated carbon preferably has a specific surface area (C) calculated by the BET method from the carbon dioxide adsorption isotherm of 860 m 2 /g or more and 1500 m 2 /g or less.
前述の活性炭は、前記二酸化炭素吸着等温線からＤＦＴ解析で算出される総細孔容積（Ｂ）が、０．３ｍｌ／ｇ以上であるとより好ましい。 The activated carbon preferably has a total pore volume (B) of 0.3 ml/g or more calculated from the carbon dioxide adsorption isotherm by DFT analysis.
前述の活性炭は、平均粒子径が５μｍ以上１５μｍ以下であるとさらに好ましい。 It is even more preferable that the average particle size of the activated carbon is 5 μm or more and 15 μm or less.
前述の活性炭は、原水処理用であると好ましい。 The aforementioned activated carbon is preferably for use in raw water treatment.
前述の活性炭は、カビ臭抑制用であると好ましい。 The activated carbon mentioned above is preferably used to suppress moldy odors.
あるいは、本発明の別の局面に係るカビ臭を抑制する方法は、前述した本発明の一局面に係る活性炭で被処理液体を処理することを含む。 Alternatively, a method for suppressing a moldy odor according to another aspect of the present invention includes treating a liquid to be treated with the activated carbon according to the aspect of the present invention described above.
本発明によれば、フミン質共存下においても２－ＭＩＢを良好に吸着することができる活性炭を提供することができる。さらに、このような活性炭で液体、特に浄水処理施設における原水を処理することによって、カビ臭を抑制することができる。 The present invention provides activated carbon that can effectively adsorb 2-MIB even in the presence of humic substances. Furthermore, by treating liquids, particularly raw water in water purification facilities, with such activated carbon, mold odors can be suppressed.
以下、本発明の実施形態について、詳細に説明する。なお、本発明の範囲はここで説明する実施形態に限定されるものではなく、本発明の趣旨を損なわない範囲で種々の変更をすることができる。 The following describes in detail an embodiment of the present invention. Note that the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention.
［活性炭］
本実施形態の活性炭は、窒素吸着等温線からＢＪＨ法で算出される細孔容積（Ａ）に対する二酸化炭素吸着等温線からＤＦＴ解析で算出される総細孔容積（Ｂ）の比率（Ｂ）／（Ａ）が、１．６以上７．０以下である多孔質の活性炭である。
[Activated carbon]
The activated carbon of this embodiment is a porous activated carbon in which the ratio (B)/(A) of the pore volume (A) calculated from the nitrogen adsorption isotherm by the BJH method to the total pore volume (B) calculated from the carbon dioxide adsorption isotherm by DFT analysis is 1.6 or more and 7.0 or less.
ＢＪＨ（Ｂａｒｒｅｔｔ－Ｊｏｙｎｅｒ－Ｈａｌｌｅｎｄａ）法とは、多孔質体のメソ孔（細孔直径２ｎｍ以上５０ｎｍ以下の細孔）の解析に用いられる方法である。本実施形態において、窒素吸着等温線からＢＪＨ法で算出される細孔容積（Ａ）（以下、単に「ＢＪＨ細孔容積（Ａ）」とも称する）とは、窒素吸着等温線からＢＪＨ法を適用することにより算出される、活性炭が有する細孔のうち細孔直径２ｎｍ以上５０ｎｍ以下の範囲のメソ孔の細孔容積（ｍｌ／ｇ）をいう。具体的には、後述する実施例に記載する方法によって測定される細孔容積（ｍｌ／ｇ）をいう。 The BJH (Barrett-Joyner-Hallenda) method is a method used to analyze mesopores (pores with a pore diameter of 2 nm to 50 nm) in porous bodies. In this embodiment, the pore volume (A) calculated from the nitrogen adsorption isotherm by the BJH method (hereinafter also simply referred to as "BJH pore volume (A)") refers to the pore volume (ml/g) of mesopores with a pore diameter in the range of 2 nm to 50 nm among the pores possessed by activated carbon, calculated by applying the BJH method from the nitrogen adsorption isotherm. Specifically, it refers to the pore volume (ml/g) measured by the method described in the examples described later.
ＤＦＴ解析（ＤＦＴ（Ｄｅｎｓｉｔｙ Ｆｕｎｃｔｉｏｎａｌ Ｔｈｅｏｒｙ）法）とは、多孔質体のミクロ孔（細孔直径２ｎｍ未満の細孔）の解析に用いられる方法である。本実施形態において、二酸化炭素吸着等温線からＤＦＴ解析で算出される総細孔容積（Ｂ）（以下、単に「ＤＦＴ総細孔容積（Ｂ）」とも称する）とは、二酸化炭素吸着等温線からＤＦＴ解析を適用することにより算出される、活性炭が有する細孔のうち細孔直径２ｎｍ未満のミクロ孔の総細孔容積（ｍｌ／ｇ）をいう。具体的には、後述する実施例に記載する方法によって測定される総細孔容積（ｍｌ／ｇ）をいう。 DFT analysis (DFT (Density Functional Theory) method) is a method used to analyze micropores (pores with a pore diameter of less than 2 nm) in porous bodies. In this embodiment, the total pore volume (B) calculated by DFT analysis from the carbon dioxide adsorption isotherm (hereinafter also simply referred to as "DFT total pore volume (B)") refers to the total pore volume (ml/g) of micropores with a pore diameter of less than 2 nm among the pores possessed by activated carbon, calculated by applying DFT analysis from the carbon dioxide adsorption isotherm. Specifically, it refers to the total pore volume (ml/g) measured by the method described in the examples described later.
活性炭のＤＦＴ総細孔容積（Ｂ）／ＢＪＨ細孔容積（Ａ）を１．６以上にすることによって、フミン質共存下においても選択的に２－ＭＩＢを良好に吸着することができると考えられる。この理由は、フミン質が吸着され易いメソ孔の細孔が少なく、一方、２－ＭＩＢが吸着され易いミクロ孔の細孔が多いことによって、フミン質の活性炭への吸着が妨げられるためと考えられる。加えて、メソ孔の細孔が少ない場合には、大分子であるフミン質が吸着されてミクロ孔の細孔を塞いでしまうことを防止すると考えられ、活性炭は良好な２－ＭＩＢの吸着性能を有すると考えられる。ＤＦＴ総細孔容積（Ｂ）／ＢＪＨ細孔容積（Ａ）は、好ましくは１．８以上、より好ましくは１．９以上、さらに好ましくは２以上、または、よりさらに好ましくは２．１以上、２．２以上、２．３以上もしくは２．３２以上である。 By making the DFT total pore volume (B)/BJH pore volume (A) of the activated carbon 1.6 or more, it is believed that 2-MIB can be selectively and effectively adsorbed even in the presence of humic substances. The reason for this is believed to be that the number of mesopores, which are easily adsorbed by humic substances, is small, while the number of micropores, which are easily adsorbed by 2-MIB, is large, which hinders the adsorption of humic substances to the activated carbon. In addition, when there are few mesopores, it is believed that the large molecules of humic substances are adsorbed and the micropores are prevented from being blocked, and the activated carbon is believed to have good 2-MIB adsorption performance. The DFT total pore volume (B)/BJH pore volume (A) is preferably 1.8 or more, more preferably 1.9 or more, even more preferably 2 or more, or even more preferably 2.1 or more, 2.2 or more, 2.3 or more, or 2.32 or more.
また、活性炭のＤＦＴ総細孔容積（Ｂ）／ＢＪＨ細孔容積（Ａ）を７．０以下とすることによって、ミクロ孔の細孔の過度の増加により活性炭の構造を変化させてその吸着機能を低下させたり、製造コストを極端に増やしてしまうことを避けることができる。ＤＦＴ総細孔容積（Ｂ）／ＢＪＨ細孔容積（Ａ）は、好ましくは７未満、より好ましくは６．５以下、または、さらに好ましくは６以下、５．５以下、５以下、４．５以下、４．２以下、４．１１以下、４．１１未満、３．５以下、３以下、２．８以下もしくは２．５以下である。 In addition, by setting the DFT total pore volume (B)/BJH pore volume (A) of the activated carbon to 7.0 or less, it is possible to avoid an excessive increase in the number of micropores, which would change the structure of the activated carbon and reduce its adsorption function, or an excessive increase in production costs. The DFT total pore volume (B)/BJH pore volume (A) is preferably less than 7, more preferably 6.5 or less, or even more preferably 6 or less, 5.5 or less, 5 or less, 4.5 or less, 4.2 or less, 4.11 or less, less than 4.11, 3.5 or less, 3 or less, 2.8 or less, or 2.5 or less.
このように、本実施形態の活性炭によると、フミン質共存下においてもカビ臭の原因の２－ＭＩＢを良好に吸着することができる。そのため、本実施形態の活性炭を、例えば浄水処理施設において原水の浄水処理用として、特にカビ臭抑制用として投入または供給等を行うことによって、好適に用いることができる。 In this way, the activated carbon of this embodiment can effectively adsorb 2-MIB, which causes moldy odors, even in the presence of humic substances. Therefore, the activated carbon of this embodiment can be suitably used, for example, by adding or supplying it to water purification facilities for raw water purification, particularly for suppressing moldy odors.
活性炭のＤＦＴ総細孔容積（Ｂ）／ＢＪＨ細孔容積（Ａ）は、例えば、後述する活性炭の原料となる炭素質材料の種類ならびに活性炭の製造の際における炭素質材料の賦活処理方法およびその処理条件（加熱温度および時間等）を適宜選択または調整することによって、その値を制御することができる。 The value of the DFT total pore volume (B)/BJH pore volume (A) of the activated carbon can be controlled, for example, by appropriately selecting or adjusting the type of carbonaceous material that is the raw material for the activated carbon, which will be described later, and the activation treatment method and treatment conditions (heating temperature, time, etc.) of the carbonaceous material during the production of the activated carbon.
また、本実施形態の活性炭は、ＤＦＴ総細孔容積（Ｂ）が０．３ｍｌ／ｇ以上であると好ましい。これは、活性炭のＤＦＴ総細孔容積（Ｂ）を０．３ｍｌ／ｇ以上とすることによって、活性炭が有するミクロ孔の総細孔容積自体が大きくなり、その結果、活性炭の２－ＭＩＢに対する吸着性能を向上させることができるためである。ＤＦＴ総細孔容積（Ｂ）は、より好ましくは０．３１ｍｌ／ｇ以上、さらに好ましくは０．３２ｍｌ／ｇ以上、または、よりさらに好ましくは０．３３ｍｌ／ｇ以上、０．３３２ｍｌ／ｇ超、０．３４ｍｌ／ｇ以上、０．３５ｍｌ／ｇ以上もしくは０．３５６ｍｌ／ｇ以上である。ＤＦＴ総細孔容積（Ｂ）の上限は、特に限定されないが、ミクロ孔の総細孔容積自体を過度に増加させて、活性炭の構造を変化させてその吸着機能に影響を与えたり、製造コストを極端に増加させない値であればよい。 In addition, the activated carbon of this embodiment preferably has a DFT total pore volume (B) of 0.3 ml/g or more. This is because by making the DFT total pore volume (B) of the activated carbon 0.3 ml/g or more, the total pore volume of the micropores of the activated carbon itself becomes large, and as a result, the adsorption performance of the activated carbon for 2-MIB can be improved. The DFT total pore volume (B) is more preferably 0.31 ml/g or more, even more preferably 0.32 ml/g or more, more preferably 0.33 ml/g or more, more than 0.332 ml/g, 0.34 ml/g or more, 0.35 ml/g or more, or 0.356 ml/g or more. The upper limit of the DFT total pore volume (B) is not particularly limited, but it may be a value that does not excessively increase the total pore volume of the micropores itself, change the structure of the activated carbon, affect its adsorption function, or extremely increase the manufacturing cost.
活性炭のＤＦＴ総細孔容積（Ｂ）についても、例えば、後述する活性炭の原料となる炭素質材料の種類ならびに活性炭の製造の際における炭素質材料の賦活処理方法およびその処理条件（加熱温度および時間等）を適宜選択または調整することによって、その値を制御することができる。例えば、活性炭の製造の際に、比較的高い加熱温度かつ短い時間でガス賦活処理を行うことによって、ＤＦＴ総細孔容積（Ｂ）（ｍｌ／ｇ）をより大きくすることができる。 The DFT total pore volume (B) of the activated carbon can also be controlled by, for example, appropriately selecting or adjusting the type of carbonaceous material used as the raw material for the activated carbon (described later) and the activation treatment method and treatment conditions (heating temperature, time, etc.) of the carbonaceous material during the production of the activated carbon. For example, the DFT total pore volume (B) (ml/g) can be increased by performing a gas activation treatment at a relatively high heating temperature for a short time during the production of the activated carbon.
本実施形態の活性炭は、二酸化炭素吸着等温線からＢＥＴ法で算出される比表面積（Ｃ）（以下、単に「ＢＥＴ比表面積（Ｃ）」とも称する）が、８６０ｍ２／ｇ以上１５００ｍ２／ｇ以下であると好ましい。本実施形態において、ＢＥＴ比表面積（Ｃ）は、二酸化炭素吸着等温線からＢＥＴ法を用いて算出される。具体的には、後述する実施例に記載する方法によって算出される値をいう。 The activated carbon of this embodiment preferably has a specific surface area (C) calculated from the carbon dioxide adsorption isotherm by the BET method (hereinafter also simply referred to as "BET specific surface area (C)") of 860 m2 /g or more and 1500 m2 /g or less. In this embodiment, the BET specific surface area (C) is calculated from the carbon dioxide adsorption isotherm by the BET method. Specifically, it refers to a value calculated by the method described in the examples described later.
ＢＥＴ比表面積（Ｃ）を８６０ｍ２／ｇ以上とすることによって、吸着可能な面積自体が大きくなり、活性炭の２－ＭＩＢに対する吸着性能を向上させることができる。一方、ＢＥＴ比表面積（Ｃ）を過度に大きすぎない値とすることによって、活性炭の構造を変化させてその吸着機能に影響を与えたり、活性炭の製造コストを極端に増加させてしまうことを避けることができる。 By setting the BET specific surface area (C) to 860 m 2 /g or more, the adsorption area itself becomes large, and the adsorption performance of the activated carbon for 2-MIB can be improved. On the other hand, by setting the BET specific surface area (C) to a value that is not too large, it is possible to avoid changing the structure of the activated carbon, which would affect its adsorption function, and to avoid an extreme increase in the production cost of the activated carbon.
ＢＥＴ比表面積（Ｃ）は、より好ましくは８６７ｍ２／ｇ以上、さらに好ましくは９００ｍ２／ｇ以上、または、よりさらに好ましくは９５０ｍ２／ｇ以上、９６８ｍ２／ｇ以上、１０００ｍ２／ｇ以上もしくは１０９３ｍ２／ｇ以上である。加えて、ＢＥＴ比表面積（Ｃ）は、より好ましくは１４００ｍ２／ｇ以下、さらに好ましくは１３５０ｍ２／ｇ以下、よりさらに好ましくは１３００ｍ２／ｇ以下である。 The BET specific surface area (C) is more preferably 867 m 2 /g or more, even more preferably 900 m 2 /g or more, or even more preferably 950 m 2 /g or more, 968 m 2 /g or more, 1000 m 2 /g or more, or 1093 m 2 /g or more. In addition, the BET specific surface area (C) is more preferably 1400 m 2 /g or less, even more preferably 1350 m 2 /g or less, and even more preferably 1300 m 2 /g or less.
活性炭のＢＥＴ比表面積（Ｃ）は、例えば、後述する活性炭の原料となる炭素質材料の種類ならびに活性炭の製造の際における炭素質材料の賦活処理方法およびその処理条件（加熱温度および時間等）を適宜選択または調整することによって、その値を制御することができる。例えば、活性炭の製造の際に、比較的高い加熱温度かつ短い時間でガス賦活処理を行うことによって、ＢＥＴ比表面積（Ｃ）（ｍ２／ｇ）をより大きくすることができる。 The BET specific surface area (C) of activated carbon can be controlled by, for example, appropriately selecting or adjusting the type of carbonaceous material used as the raw material for activated carbon described below, and the activation treatment method and treatment conditions (heating temperature, time, etc.) of the carbonaceous material during the production of activated carbon. For example, the BET specific surface area (C) ( m2 /g) can be increased by performing a gas activation treatment at a relatively high heating temperature for a short time during the production of activated carbon.
本実施形態の活性炭の形状は、２－ＭＩＢを吸着可能であれば、特に限定されない。例えば、活性炭は、粉末状、粒子状、繊維状（糸状、織り布（クロス）状、フェルト状）等のいずれの形状でもよく、具体的な使用態様に応じて適宜選択できる。これらのうち、単位体積当たりの吸着性能が高いという観点から、本実施形態の活性炭の形状は粉末状が好ましい。 The shape of the activated carbon in this embodiment is not particularly limited as long as it is capable of adsorbing 2-MIB. For example, the activated carbon may be in any shape, such as powder, particles, or fibers (thread, woven fabric (cloth), felt), etc., and can be appropriately selected depending on the specific mode of use. Of these, from the viewpoint of high adsorption performance per unit volume, the activated carbon in this embodiment is preferably in powder form.
本実施形態の活性炭が粉末状である場合、その平均粒子径は特に限定されないが、２０μｍ以下であると好ましく、５μｍ以上１５μｍ以下であるとより好ましい。活性炭の平均粒子径を２０μｍ以下とすることによって、各々の粉末状の活性炭に２－ＭＩＢが接触し易くなるため、活性炭による吸着性能を向上させることができる。一方、平均粒子径が５μｍ未満である場合、凝集沈殿法や急速濾過法等の処理工程で活性炭漏れや目詰まり等が発生する可能性があり、また、粉砕に掛かる費用が高くなる。本実施形態において、平均粒子径（μｍ）は、体積基準の累計粒度分布における５０％粒子径をいう。平均粒子径（μｍ）はレーザー回折・散乱法により測定することができる。具体的には、後述する実施例に記載する方法によって算出される平均粒子径（μｍ）の値をいう。 When the activated carbon of this embodiment is in powder form, its average particle size is not particularly limited, but is preferably 20 μm or less, and more preferably 5 μm to 15 μm. By making the average particle size of the activated carbon 20 μm or less, it becomes easier for 2-MIB to come into contact with each powdered activated carbon, and the adsorption performance of the activated carbon can be improved. On the other hand, if the average particle size is less than 5 μm, there is a possibility that activated carbon leakage or clogging may occur in the treatment process such as the coagulation sedimentation method or the rapid filtration method, and the cost of pulverization will be high. In this embodiment, the average particle size (μm) refers to the 50% particle size in the cumulative particle size distribution based on volume. The average particle size (μm) can be measured by a laser diffraction/scattering method. Specifically, it refers to the value of the average particle size (μm) calculated by the method described in the examples described later.
活性炭の平均粒子径は、より好ましくは１５μｍ未満、さらに好ましくは１４μｍ以下、よりさらに好ましくは１２μｍ以下である。加えて、平均粒子径は、より好ましくは８μｍ以上、さらに好ましくは１０μｍ以上、よりさらに好ましくは１１．７μｍ以上である。 The average particle size of the activated carbon is more preferably less than 15 μm, even more preferably 14 μm or less, and even more preferably 12 μm or less. In addition, the average particle size is more preferably 8 μm or more, even more preferably 10 μm or more, and even more preferably 11.7 μm or more.
活性炭の平均粒子径は、例えば、後述する活性炭の原料となる炭素質材料の種類と必要に応じて行う粉砕処理方法および／または篩分処理方法ならびにその処理条件とを適宜選択または調整することによって、その数値を制御することができる。 The average particle size of the activated carbon can be controlled, for example, by appropriately selecting or adjusting the type of carbonaceous material that is the raw material for the activated carbon (described below) and the crushing method and/or sieving method and processing conditions that are performed as necessary.
［活性炭の製造方法］
本実施形態の活性炭を製造する方法は、最終的に、活性炭のＤＦＴ総細孔容積（Ｂ）／ＢＪＨ細孔容積（Ａ）の比率（Ｂ）／（Ａ）が１．６以上７．０以下となっていれば、特に限定されない。
[Method of producing activated carbon]
The method for producing the activated carbon of this embodiment is not particularly limited as long as the ratio (B)/(A) of the DFT total pore volume (B) to the BJH pore volume (A) of the activated carbon is ultimately 1.6 or more and 7.0 or less.
活性炭は、原料となる炭素質材料に対して必要に応じて炭化処理を行った後、賦活処理、ならびに必要に応じて洗浄処理、乾燥処理および粉砕処理を行うことによって得ることができる。 Activated carbon can be obtained by subjecting the raw carbonaceous material to a carbonization process as necessary, followed by an activation process, and, as necessary, a washing process, a drying process, and a pulverization process.
このような炭素質材料としては、特に限定されないが、例えば植物系炭素質材料（例えば、木材、鉋屑、木炭、ヤシ殻やクルミ殻などの果実殻、果実種子、パルプ製造副生成物、リグニン、廃糖蜜などの植物由来の材料）、鉱物系炭素質材料（例えば、泥炭、亜炭、褐炭、瀝青炭、無煙炭、コークス、コールタール、石炭ピッチ、石油蒸留残渣、石油ピッチなどの鉱物由来の材料）、合成樹脂系炭素質材料（例えば、フェノール樹脂、ポリ塩化ビニリデン、アクリル樹脂などの合成樹脂由来の材料）、天然繊維系炭素質材料（例えば、セルロースなどの天然繊維、レーヨンなどの再生繊維などの天然繊維由来の材料）等が挙げられる。これらの炭素質材料は、単独で使用してもよく、または２種類以上を組み合わせて使用することができる。 Such carbonaceous materials are not particularly limited, but examples thereof include plant-based carbonaceous materials (e.g., plant-derived materials such as wood, sawdust, charcoal, fruit shells such as coconut shells and walnut shells, fruit seeds, pulp manufacturing by-products, lignin, and blackstrap molasses), mineral-based carbonaceous materials (e.g., mineral-derived materials such as peat, lignite, brown coal, bituminous coal, anthracite, coke, coal tar, coal pitch, petroleum distillation residue, and petroleum pitch), synthetic resin-based carbonaceous materials (e.g., synthetic resin-derived materials such as phenolic resin, polyvinylidene chloride, and acrylic resin), and natural fiber-based carbonaceous materials (e.g., natural fibers such as cellulose, and regenerated fibers such as rayon). These carbonaceous materials may be used alone or in combination of two or more types.
これらのうち、大量に入手することができ、商業的に有利であるという観点から、植物系炭素質材料が好ましい。活性炭の原料を植物系炭素質材料から選択することによって、後述する賦活処理条件の調整等によるＤＦＴ総細孔容積（Ｂ）／ＢＪＨ細孔容積（Ａ）の制御を比較的容易に行うことができる。さらに、植物系炭素質材料のうち、活性炭による２－ＭＩＢの吸着性能が高いという観点から、ヤシ殻または木材がより好ましく、ヤシ殻がさらに好ましい。 Of these, plant-based carbonaceous materials are preferred from the viewpoint of being available in large quantities and being commercially advantageous. By selecting the raw material for activated carbon from plant-based carbonaceous materials, it is relatively easy to control the DFT total pore volume (B)/BJH pore volume (A) by adjusting the activation treatment conditions described below. Furthermore, of the plant-based carbonaceous materials, coconut shells or wood are more preferred, and coconut shells are even more preferred, from the viewpoint of high adsorption performance of 2-MIB by activated carbon.
炭化処理を必要とする場合、これらの炭素質材料に対して、通常、酸素または空気を遮断した環境下において、例えば４００℃以上８００℃以下、好ましくは５００℃以上８００℃以下、さらに好ましくは５５０℃以上７５０℃以下程度で炭化処理を行うことができる。その後、必要に応じて粒度調整を行ってもよい。 When carbonization is required, these carbonaceous materials can be carbonized, typically in an environment that is free of oxygen or air, at a temperature of, for example, 400°C to 800°C, preferably 500°C to 800°C, and more preferably 550°C to 750°C. After that, particle size adjustment may be performed as necessary.
その後、炭素質材料に対して賦活処理を行う。賦活処理とは、炭素質材料の表面に細孔を形成し、多孔質体である活性炭に変える処理である。これにより所望するＤＦＴ総細孔容積（Ｂ）／ＢＪＨ細孔容積（Ａ）を有する活性炭を得ることができる。賦活処理は、当該技術分野において一般的な方法により行うことができ、特に限定されず、主に、ガス賦活処理または薬剤賦活処理の２種類の処理方法を挙げることができる。これらのうち、浄水処理用として使用する場合、不純物の残留が少ないという観点から、ガス賦活処理が好ましい。 Then, the carbonaceous material is subjected to an activation treatment. The activation treatment is a treatment in which pores are formed on the surface of the carbonaceous material, turning it into a porous body, activated carbon. This makes it possible to obtain activated carbon having the desired DFT total pore volume (B)/BJH pore volume (A). The activation treatment can be performed by a method common in the technical field, and is not particularly limited. Two main types of treatment methods include gas activation treatment and chemical activation treatment. Of these, when used for water purification treatment, gas activation treatment is preferred from the viewpoint of leaving less impurities behind.
ガス賦活処理は、例えば、水蒸気、二酸化炭素、空気、酸素、燃焼ガス、またはこれらの混合ガスの存在下で、炭素質材料を加熱する処理である。加熱は、例えば８００℃以上１５００℃以下、好ましくは８５０℃以上１２００℃以下、より好ましくは９００℃以上１１００℃以下の温度において行われる。薬剤賦活処理としては、例えば、塩化亜鉛、塩化カルシウム、リン酸、硫酸、水酸化ナトリウム、水酸化カリウム、水酸化マグネシウム、水酸化カルシウム等の賦活剤を炭素質材料と混合し、不活性ガス雰囲気下で加熱する公知の方法で行ってもよい。 The gas activation process is, for example, a process in which the carbonaceous material is heated in the presence of water vapor, carbon dioxide, air, oxygen, combustion gas, or a mixture of these gases. Heating is performed, for example, at a temperature of 800°C to 1500°C, preferably 850°C to 1200°C, and more preferably 900°C to 1100°C. The chemical activation process may be performed by a known method in which an activator such as zinc chloride, calcium chloride, phosphoric acid, sulfuric acid, sodium hydroxide, potassium hydroxide, magnesium hydroxide, or calcium hydroxide is mixed with the carbonaceous material and heated in an inert gas atmosphere.
これらのうち、ガス賦活処理で炭素質材料を賦活させることによって、活性炭のＤＦＴ総細孔容積（Ｂ）／ＢＪＨ細孔容積（Ａ）を１．６以上７．０以下に容易に制御することができる。具体的には、上述したような比較的高い加熱温度かつ短い時間でガス賦活処理（好ましくは水蒸気賦活処理）を行うことによって、活性炭におけるメソ孔の細孔容積に対するミクロ孔の総細孔容積の比率を１．６以上７．０以下の範囲内に収まるようにすることができる。 Among these, by activating the carbonaceous material by gas activation treatment, the DFT total pore volume (B)/BJH pore volume (A) of the activated carbon can be easily controlled to 1.6 or more and 7.0 or less. Specifically, by performing gas activation treatment (preferably steam activation treatment) at a relatively high heating temperature and for a short time as described above, the ratio of the total pore volume of micropores to the pore volume of mesopores in the activated carbon can be set to fall within the range of 1.6 or more and 7.0 or less.
賦活処理後の活性炭は、必要に応じて洗浄および乾燥する。具体的には、アルカリ金属、アルカリ土類金属および遷移金属等の不純物を含むヤシ殻等の植物系炭素質材料または鉱物系炭素質材料を活性炭の原料とした場合、灰分や薬剤等を除去するために洗浄する。洗浄には鉱酸や水が用いられ、鉱酸としては洗浄効率の高い塩酸が好ましい。 After activation treatment, the activated carbon is washed and dried as necessary. Specifically, when the raw material for activated carbon is a plant-based carbonaceous material such as coconut shell or a mineral-based carbonaceous material containing impurities such as alkali metals, alkaline earth metals, and transition metals, it is washed to remove ash, chemicals, etc. Mineral acid and water are used for washing, and hydrochloric acid, which has a high cleaning efficiency, is preferred as the mineral acid.
賦活処理後の活性炭は、必要に応じて粉砕処理および／または篩分処理される。粉砕処理は、一般的に活性炭の粉砕に用いられる粉砕装置、例えば、エロフォールミル、ロッドミル、ローラーミル、ハンマーミル、ブレードミル、ピンミル等の高速回転ミル、ボールミル、ジェットミル等を用いて行うことができる。 The activated carbon after the activation treatment is crushed and/or sieved as necessary. The crushing treatment can be carried out using a crushing device generally used for crushing activated carbon, such as aeroform mills, rod mills, roller mills, hammer mills, blade mills, pin mills, and other high-speed rotating mills, ball mills, jet mills, etc.
本実施形態の活性炭は、単独で使用してもよく、必要に応じて他の成分と組み合わせて用いてもよい。他の成分としては、例えば、ハロゲン化物、他の臭気成分を除去するための吸着剤（例えば、ゼオライト、シリカ等のケイ酸塩系吸着剤、薬品無担持活性炭、薬品担持活性炭等）等を挙げることができる。 The activated carbon of this embodiment may be used alone or in combination with other components as necessary. Examples of other components include adsorbents for removing halides and other odorous components (e.g., zeolite, silicate-based adsorbents such as silicate, chemical-free activated carbon, chemical-supported activated carbon, etc.).
［カビ臭を抑制する方法］
本実施形態のカビ臭を抑制する方法は、前述した活性炭で被処理液体を処理することを含む。
[Methods to suppress moldy odor]
The method for suppressing a moldy odor in this embodiment includes treating the liquid to be treated with the activated carbon described above.
被処理液体は、２－ＭＩＢを含有する液体であればどのような液体でも構わないが、例えば、原水、水道水、工業用水、廃水、家庭用飲料水等が挙げられる。フミン質共存下で２－ＭＩＢを吸着する必要があるという観点から、これらのうち浄水処理施設での原水処理において、本実施形態の方法は有用に適用される。具体的には、例えば、タンク等に貯蔵された河川または湖水等の水源からの原水に、前述した実施形態の活性炭をそのまま、または湿潤状態で投入または供給等を行う。活性炭の供給量は特に限定されず、適宜所望の必要量に応じて供給すればよい。 The liquid to be treated may be any liquid containing 2-MIB, including raw water, tap water, industrial water, wastewater, and household drinking water. From the viewpoint that 2-MIB must be adsorbed in the presence of humic substances, the method of this embodiment is usefully applied to raw water treatment at water purification facilities. Specifically, the activated carbon of the above-mentioned embodiment is introduced or supplied as is or in a wet state to raw water from a water source such as a river or lake water stored in a tank or the like. The amount of activated carbon supplied is not particularly limited, and may be supplied as needed according to the desired amount.
以下に、実施例により本発明をさらに具体的に説明するが、本発明は実施例により何ら限定されるものではない。 The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.
各実施例および各比較例の活性炭の物性値およびフミン酸共存下での２－ＭＩＢ吸着量は、以下に示す方法により測定した。 The physical properties of the activated carbon in each Example and Comparative Example and the amount of 2-MIB adsorption in the presence of humic acid were measured using the methods described below.
［平均粒子径（μｍ）の測定］
活性炭（具体的には粉末活性炭）の平均粒子径は、レーザー回折測定法により測定した。具体的には、測定対象である活性炭、界面活性剤およびイオン交換水を混合して分散液を得て、レーザー回折・散乱式粒子径分布測定装置（マイクロトラック・ベル社製、「ＭＴ３３００ＩＩ」）を用い、透過法により活性炭の平均粒子径を測定した。分散液における活性炭の濃度は、当該測定装置で表示される測定濃度範囲に収まるように調整した。界面活性剤としては、和光純薬工業社製の「ポリオキシエチレン（１０）オクチルフェニルエーテル」を用い、測定に影響する気泡等が発生しない適当な量を添加および混合した。分析条件を以下に示す。
[Measurement of average particle size (μm)]
The average particle size of activated carbon (specifically, powdered activated carbon) was measured by laser diffraction measurement. Specifically, the activated carbon to be measured, the surfactant, and ion-exchanged water were mixed to obtain a dispersion, and the average particle size of the activated carbon was measured by a transmission method using a laser diffraction/scattering particle size distribution measuring device (Microtrack Bell, "MT3300II"). The concentration of activated carbon in the dispersion was adjusted to fall within the measurement concentration range displayed by the measuring device. As the surfactant, "Polyoxyethylene (10) Octylphenyl Ether" manufactured by Wako Pure Chemical Industries, Ltd. was used, and an appropriate amount was added and mixed so that bubbles that would affect the measurement would not be generated. The analysis conditions are shown below.
（分析条件）
測定回数：１回
測定時間：３０秒
分布表示：体積
粒径区分：標準
計算モード：ＭＴ３０００ＩＩ
溶媒名：ＷＡＴＥＲ
測定上限：２０００μｍ、測定下限：０．０２１μｍ
残分比：０．００
通過分比：０．００
残分比設定：無効
粒子透過性：透過
粒子屈折率：１．８１
粒子形状：非球形
溶媒屈折率：１．３３３
ＤＶ値：０．０１５０～０．０７００
透過率（ＴＲ）：０．７００～０．９５０
測定結果において、体積基準の累計粒度分布における５０％粒子径であるＤ５０の値を平均粒子径（μｍ）とした。
(Analysis conditions)
Number of measurements: 1 Measurement time: 30 seconds Distribution display: Volume Particle size classification: Standard Calculation mode: MT3000II
Solvent name: WATER
Upper limit of measurement: 2000 μm, lower limit of measurement: 0.021 μm
Residual ratio: 0.00
Passing ratio: 0.00
Residual ratio setting: Disabled Particle transmittance: Transmitted Particle refractive index: 1.81
Particle shape: non-spherical Solvent refractive index: 1.333
DV value: 0.0150 to 0.0700
Transmittance (TR): 0.700 to 0.950
In the measurement results, the value of D50, which is the 50% particle diameter in the cumulative particle size distribution on a volume basis, was taken as the average particle diameter (μm).
［二酸化炭素吸着等温線の測定］
ガス吸着測定装置（Ｑｕａｎｔａｃｈｒｏｍｅ社製、「ＡＵＴＯＳＯＲＢ－ｉＱ ＭＰ－ＸＲ」）を使用し、測定対象である活性炭の２７３Ｋにおける二酸化炭素の吸着を相対圧Ｐ／Ｐ０＝０．０００７５～０．０３０の範囲で測定することにより、当該活性炭の二酸化炭素吸着等温線を得た。
[Measurement of Carbon Dioxide Adsorption Isotherm]
A gas adsorption measuring device ("AUTOSORB-iQ MP-XR" manufactured by Quantachrome) was used to measure the adsorption of carbon dioxide by the activated carbon to be measured at 273 K in a relative pressure range of P/P0 = 0.00075 to 0.030, thereby obtaining a carbon dioxide adsorption isotherm for the activated carbon.
［窒素吸着等温線の測定］
ガス吸着測定装置（マイクロトラック・ベル社製、「ＢＥＬＳＯＲＰ－ｍｉｎｉ」）を使用し、測定対象である活性炭を窒素気流下（窒素流量：５０ｍＬ／分）にて３００℃で３時間加熱した後、７７Ｋにおける当該活性炭の窒素吸着等温線を測定した。
[Measurement of Nitrogen Adsorption Isotherm]
Using a gas adsorption measuring device (Microtrac-Bel, "BELSORP-mini"), the activated carbon to be measured was heated at 300° C. for 3 hours under a nitrogen flow (nitrogen flow rate: 50 mL/min), and then the nitrogen adsorption isotherm of the activated carbon at 77 K was measured.
［二酸化炭素吸着等温線によるＢＥＴ比表面積（Ｃ）（ｍ２／ｇ）の測定］
上記方法により得られた二酸化炭素吸着等温線において、相対圧Ｐ／Ｐ０＝０．０２４７～０．０２８５の範囲のデータを用いてＢＥＴ法による解析を行い、測定対象である活性炭のＢＥＴ比表面積（Ｃ）（ｍ２／ｇ）を算出した。
[Measurement of BET specific surface area (C) (m 2 /g) by carbon dioxide adsorption isotherm]
In the carbon dioxide adsorption isotherm obtained by the above method, analysis was performed by the BET method using data in the relative pressure range P/P0 = 0.0247 to 0.0285, and the BET specific surface area (C) (m 2 /g) of the activated carbon to be measured was calculated.
［窒素吸着等温線によるＢＪＨ細孔容積（Ａ）（ｍｌ／ｇ）の測定］
上記方法により得られた窒素吸着等温線において、ＢＪＨ法を適用し、相対圧Ｐ／Ｐ０＝０．９９以下の範囲において、測定対象である活性炭が有する細孔のうち細孔直径２ｎｍ以上５０ｎｍ以下の範囲のＢＪＨ細孔容積（Ａ）（ｍｌ／ｇ）を算出した。ＢＪＨ法での解析では、マイクロトラック・ベル社製から提供された基準ｔ曲線「ＮＧＣＢ－ＢＥＬ．ｔ」を解析に用いた。
[Measurement of BJH pore volume (A) (ml/g) by nitrogen adsorption isotherm]
The BJH method was applied to the nitrogen adsorption isotherm obtained by the above method, and the BJH pore volume (A) (ml/g) of the pores in the measurement target activated carbon with a pore diameter in the range of 2 nm to 50 nm was calculated in the relative pressure range of P/P0 = 0.99 or less. In the analysis by the BJH method, the standard t curve "NGCB-BEL.t" provided by Microtrac-Bel was used for the analysis.
［二酸化炭素吸着等温線によるＤＦＴ総細孔容積（Ｂ）（ｍｌ／ｇ）の測定方法］
上記方法により得られた二酸化炭素吸着等温線において、Ｃａｌｃｕｌａｔｉｏｎ ｍｏｄｅｌとして「ＣＯ２ ａｔ ２７３Ｋ ｏｎ ｃａｒｂｏｎ（ＮＬＤＦＴ ｍｏｄｅｌ）」を適用してＮＬＤＦＴ法での解析を行い、細孔径分布を求め、各細孔直径範囲における細孔容積を測定し、測定対象である活性炭が有する細孔のうち細孔直径２ｎｍ未満のＤＦＴ総細孔容積（Ｂ）（ｍｌ／ｇ）を算出した。
[Method for measuring DFT total pore volume (B) (ml/g) by carbon dioxide adsorption isotherm]
In the carbon dioxide adsorption isotherm obtained by the above method, analysis was performed by the NLDFT method using "CO 2 at 273K on carbon (NLDFT model)" as the calculation model to obtain the pore size distribution, measure the pore volume in each pore diameter range, and calculate the DFT total pore volume (B) (ml/g) of pores with a pore diameter of less than 2 nm in the activated carbon to be measured.
［フミン酸共存下での２－ＭＩＢ吸着量（ｎｇ／ｍｇ）の測定］
以下に、後述する実施例１の活性炭における当該２－ＭＩＢ吸着量（ｎｇ／ｍｇ）の測定方法を詳細に示す。後述する他の実施例および比較例における活性炭についても同様の方法で当該２－ＭＩＢ吸着量の測定を行った。
[Measurement of 2-MIB adsorption amount (ng/mg) in the presence of humic acid]
The following describes in detail the method for measuring the 2-MIB adsorption amount (ng/mg) of the activated carbon in Example 1. The 2-MIB adsorption amounts of the activated carbons in the other Examples and Comparative Examples were also measured in the same manner.
（１）フミン酸試薬の調整原液の作製
乾燥質量換算で９．９ｇのフミン酸試薬（和光純薬社製）を５００ｍｌの三角フラスコ内に測り取った。次いで、三角フラスコに、１Ｎ・ＮａＯＨを３００ｍｌ加えて２００ｒｐｍで３０分間振とうさせた。その後、溶液をビーカーに移し、攪拌しながら（１＋１）Ｈ２ＳＯ４（体積割合でＨ２ＳＯ４を１に対してＨ２Ｏを１含む硫酸溶液）を加えて、ｐＨ＝４．５に調整した。ｐＨ調整後、沈殿管に移し、５０００ｒｐｍで１０分間遠心分離を行った。遠心分離後、溶液と沈殿物とを濾別し、溶液に１Ｎ・ＮａＯＨを攪拌しながら加えて、ｐＨ＝６．５に調整した。このように調整したフミン酸溶液に、ｐＨ＝７．４のリン酸緩衝液を当該フミン酸溶液の１／２０容量において加えた。その後、当該溶液を０．４５μｍメンブレンフィルターを用いて吸引ろ過して、フミン酸試薬の調製原液とした。
(1) Preparation of humic acid reagent stock solution 9.9 g of humic acid reagent (manufactured by Wako Pure Chemical Industries, Ltd.) was weighed in a 500 ml Erlenmeyer flask in terms of dry mass. Next, 300 ml of 1N NaOH was added to the Erlenmeyer flask and shaken at 200 rpm for 30 minutes. The solution was then transferred to a beaker and (1+1) H 2 SO 4 (a sulfuric acid solution containing 1 H 2 SO 4 and 1 H 2 O by volume ratio) was added while stirring to adjust the pH to 4.5. After pH adjustment, the solution was transferred to a precipitation tube and centrifuged at 5000 rpm for 10 minutes. After centrifugation, the solution and precipitate were filtered off, and 1N NaOH was added to the solution while stirring to adjust the pH to 6.5. To the humic acid solution thus adjusted, a phosphate buffer solution with a pH of 7.4 was added at 1/20 volume of the humic acid solution. Thereafter, the solution was suction filtered using a 0.45 μm membrane filter to obtain a stock solution of humic acid reagent.
（２）２－ＭＩＢ－フミン酸混合液の作製
次いで、このように調製したフミン酸試薬の調整原液と、２－ＭＩＢ標準液（富士フィルム和光純薬社製、「２－メチルイソボルネオール標準液（０．１ｍｇ／ｍｌメタノール溶液）」）とを水に混合して、２－ＭＩＢ濃度が４００ｎｇ／Ｌであり、フミン酸濃度がＴＯＣ（Ｔｏｔａｌ Ｏｒｇａｎｉｃ Ｃａｒｂｏｎ）濃度として１ｐｐｍ、４ｐｐｍ、６ｐｐｍまたは８ｐｐｍである４種類の２－ＭＩＢ－フミン酸混合液を調製した。
(2) Preparation of 2-MIB-humic acid mixed solution Next, the thus-prepared humic acid reagent stock solution and a 2-MIB standard solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., "2-methylisoborneol standard solution (0.1 mg/ml methanol solution)") were mixed in water to prepare four types of 2-MIB-humic acid mixed solutions having a 2-MIB concentration of 400 ng/L and humic acid concentrations of 1 ppm, 4 ppm, 6 ppm, or 8 ppm in terms of TOC (Total Organic Carbon) concentration.
（３）活性炭懸濁液の作製
約０．２ｇ（乾燥品で秤量）の後述する実施例１の活性炭を蒸留水１Ｌに分散させた懸濁液を作製した。
(3) Preparation of Activated Carbon Suspension About 0.2 g (weighed on a dry basis) of the activated carbon of Example 1 described below was dispersed in 1 L of distilled water to prepare a suspension.
（４）フミン酸ＴＯＣ濃度１ｐｐｍにおける２－ＭＩＢ吸着量の測定
上記（２）で調整したフミン酸ＴＯＣ濃度１ｐｐｍの２－ＭＩＢ－フミン酸混合液を用いて試験を行った。まず、この２－ＭＩＢ－フミン酸混合液を１００ｍｌずつ５つのビーカーに入れ、これらのビーカーに上記（３）で調製した活性炭懸濁液をそれぞれ０ｍｌ、２ｍｌ、３ｍｌ、５ｍｌまたは８ｍｌずつ加え、さらに蒸留水をそれぞれに加えて全量を２００ｍｌとした。得られた混合液を、振とう恒温槽（タイテック社製、「振とう恒温槽クールバスシェーカー ＭＬ－１０Ｆ」）を用いて、２５℃、１５０回／分、振幅４ｃｍの条件で６０分間振とうした。その後、３０分間静置した後、上澄み液を孔径０．４５μｍのメンブレンフィルター（Ｓａｒｔｏｒｉｕｓ社製、「ＮＭＬシリンジフィルター」）を用いた加圧濾過によって濾過した。得られた濾液について、残留している２－ＭＩＢの濃度（ｎｇ／Ｌ）をそれぞれ測定した。両対数方眼紙の縦軸に活性炭の質量当たりの２－ＭＩＢの吸着量（ｎｇ／ｍｇ）を、横軸に残留している２－ＭＩＢの濃度（２－ＭＩＢ平衡濃度、ｎｇ／Ｌ）をとり、各数値をプロットし回帰直線を引いた。２－ＭＩＢ平衡濃度が初期値の１／１０である２０ｎｇ／Ｌとなった際の２－ＭＩＢの吸着量を、フミン酸ＴＯＣ濃度１ｐｐｍにおける活性炭の吸着量とした。
(4) Measurement of 2-MIB adsorption amount at humic acid TOC concentration of 1 ppm A test was carried out using the 2-MIB-humic acid mixture with a humic acid TOC concentration of 1 ppm prepared in (2) above. First, 100 ml of this 2-MIB-humic acid mixture was placed in five beakers, and 0 ml, 2 ml, 3 ml, 5 ml, or 8 ml of the activated carbon suspension prepared in (3) above was added to each of these beakers, and distilled water was added to each beaker to make the total amount 200 ml. The resulting mixture was shaken for 60 minutes using a shaking thermostatic bath (manufactured by Taitec, "Shaking Thermostatic Bath Shaker ML-10F") at 25°C, 150 times/min, and an amplitude of 4 cm. After leaving it to stand for 30 minutes, the supernatant was filtered by pressure filtration using a membrane filter with a pore size of 0.45 μm (manufactured by Sartorius, "NML Syringe Filter"). The concentration (ng/L) of residual 2-MIB in each of the obtained filtrates was measured. The vertical axis of a double logarithmic graph paper was the adsorption amount of 2-MIB per mass of activated carbon (ng/mg) and the horizontal axis was the concentration of residual 2-MIB (2-MIB equilibrium concentration, ng/L), and the values were plotted to draw a regression line. The amount of 2-MIB adsorption when the 2-MIB equilibrium concentration reached 20 ng/L, which was 1/10 of the initial value, was regarded as the amount of 2-MIB adsorption by activated carbon at a humic acid TOC concentration of 1 ppm.
（５）フミン酸ＴＯＣ濃度３ｐｐｍにおける２－ＭＩＢ吸着量の測定
上記（４）と同様にして、フミン酸ＴＯＣ濃度が４ｐｐｍ、６ｐｐｍまたは８ｐｐｍである各混合液についても試験を行った。各試験において、２－ＭＩＢ平衡濃度が初期値の１／１０である２０ｎｇ／Ｌとなった際の２－ＭＩＢの吸着量を測定した。新たに、縦軸に２０ｎｇ／Ｌでの２－ＭＩＢ吸着量を、横軸にフミン酸ＴＯＣ濃度をとり、各数値をプロットしグラフを作成した。フミン酸ＴＯＣ濃度が３ｐｐｍの際の２－ＭＩＢ吸着量（ｎｇ／ｍｇ）を、実施例１の活性炭の２－ＭＩＢ吸着量の値（ｎｇ／ｍｇ）として読み取った。
(5) Measurement of 2-MIB adsorption amount at humic acid TOC concentration of 3 ppm In the same manner as in (4) above, tests were also conducted on each mixed solution having a humic acid TOC concentration of 4 ppm, 6 ppm, or 8 ppm. In each test, the amount of 2-MIB adsorption was measured when the 2-MIB equilibrium concentration was 20 ng/L, which is 1/10 of the initial value. A new graph was created by plotting the 2-MIB adsorption amount at 20 ng/L on the vertical axis and the humic acid TOC concentration on the horizontal axis. The 2-MIB adsorption amount (ng/mg) at a humic acid TOC concentration of 3 ppm was read as the value (ng/mg) of the 2-MIB adsorption amount of the activated carbon of Example 1.
なお、各実施例および各比較例の活性炭は、以下のように製造および入手した。 The activated carbon in each example and comparative example was manufactured and obtained as follows:
＜実施例１＞
原料である炭化したヤシ殻炭を１０００℃に加熱した流動賦活炉に投入し、水蒸気分圧５０％の条件下で、賦活処理後のヤシ殻炭のヨウ素吸着量が１５００ｍｇ／ｇになるように水蒸気賦活を行った。ヨウ素吸着量はＪＩＳ Ｋ １４７４（２０１４）に準拠して測定した（後述する実施例２および比較例１～２も同様）。その後、賦活処理後のヤシ殻炭を、粉砕機を用いて調整しながら粉末状に粉砕し、平均粒子径１２μｍの粉末状の活性炭を得た。得られた粉末状の活性炭について各物性値を測定し、フミン酸共存下での２－ＭＩＢ吸着量を評価した。測定された各物性値および評価結果を、後の表１にまとめて示す。
Example 1
The raw material, carbonized coconut shell charcoal, was placed in a fluidized bed activation furnace heated to 1000°C, and activated with water vapor under a condition of a water vapor partial pressure of 50% so that the iodine adsorption amount of the coconut shell charcoal after activation treatment was 1500 mg/g. The iodine adsorption amount was measured in accordance with JIS K 1474 (2014) (the same applies to Example 2 and Comparative Examples 1 and 2 described later). Thereafter, the coconut shell charcoal after activation treatment was pulverized into powder while adjusting it using a pulverizer, and a powdered activated carbon with an average particle size of 12 μm was obtained. The physical properties of the obtained powdered activated carbon were measured, and the 2-MIB adsorption amount in the presence of humic acid was evaluated. The measured physical properties and evaluation results are summarized in Table 1 below.
＜実施例２＞
ヨウ素吸着量が１３００ｍｇ／ｇになるように水蒸気賦活を行った以外は、実施例１と同様にして、賦活処理後のヤシ殻炭を得た。その後、賦活処理後のヤシ殻炭を、粉砕機を用いて調整しながら粉末状に粉砕し、平均粒子径１１．７μｍの粉末状の活性炭を得た。得られた粉末状の活性炭について各物性値を測定し、フミン酸共存下での２－ＭＩＢ吸着量を評価した。測定された各物性値および評価結果を、後の表１にまとめて示す。
Example 2
Except for performing steam activation so that the iodine adsorption amount was 1,300 mg/g, coconut shell charcoal after activation treatment was obtained in the same manner as in Example 1. The coconut shell charcoal after activation treatment was then pulverized into powder while adjusting the size using a pulverizer, to obtain powdered activated carbon with an average particle size of 11.7 μm. The physical properties of the obtained powdered activated carbon were measured, and the 2-MIB adsorption amount in the presence of humic acid was evaluated. The measured physical properties and evaluation results are summarized in Table 1 below.
＜比較例１＞
原料である炭化したヤシ殻炭を８５０℃に加熱した流動賦活炉に投入し、水蒸気分圧１５％の条件下で、賦活処理後のヤシ殻炭においてヨウ素吸着量が１０００ｍｇ／ｇになるように水蒸気賦活を行った。その後、賦活処理後のヤシ殻炭を、粉砕機を用いて調整しながら粉末状に粉砕し、平均粒子径１１．６μｍの粉末状の活性炭を得た。得られた粉末状の活性炭について各物性値を測定し、フミン酸共存下での２－ＭＩＢ吸着量を評価した。測定された各物性値および評価結果を、後の表１にまとめて示す。
<Comparative Example 1>
The raw material, carbonized coconut shell charcoal, was placed in a fluidized activation furnace heated to 850°C, and activated with water vapor under a condition of a water vapor partial pressure of 15% so that the coconut shell charcoal after activation had an iodine adsorption amount of 1000 mg/g. The coconut shell charcoal after activation was then pulverized into powder while adjusting the size using a pulverizer, to obtain powdered activated carbon with an average particle size of 11.6 μm. The physical properties of the obtained powdered activated carbon were measured, and the 2-MIB adsorption amount in the presence of humic acid was evaluated. The measured physical properties and evaluation results are summarized in Table 1 below.
＜比較例２（参考例）＞
原料として木質系材料が用いられている市販品の活性炭（上海興長社製、商品名「ＷＰ１６０－０５」）について、その平均粒子径および各物性値を測定し、フミン酸共存下での２－ＭＩＢ吸着量を評価した。測定された各物性値および評価結果を、後の表１にまとめて示す。
<Comparative Example 2 (Reference Example)>
The average particle size and various physical properties of a commercially available activated carbon (manufactured by Shanghai Kocho Co., Ltd., product name "WP160-05") that uses wood-based materials as the raw material were measured, and the amount of 2-MIB adsorbed in the presence of humic acid was evaluated. The measured physical properties and evaluation results are summarized in Table 1 below.
実施例１～２および比較例１～２の各物性値および評価結果は以下の表１に示す通りであった。 The physical properties and evaluation results of Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1 below.
上記表１に示すように、ＤＦＴ総細孔容積（Ｂ）／ＢＪＨ細孔容積（Ａ）の比率（Ｂ）／（Ａ）が１．６以上７．０以下の範囲内にある実施例１および２の活性炭は、２－ＭＩＢ吸着量が多かった。一方で、前述の比率（Ｂ）／（Ａ）が１．６未満または７より大きい比較例１～２の２－ＭＩＢ吸着量は少なかった。 As shown in Table 1 above, the activated carbons of Examples 1 and 2, in which the ratio (B)/(A) of the DFT total pore volume (B) to the BJH pore volume (A) was within the range of 1.6 to 7.0, had a large amount of 2-MIB adsorption. On the other hand, the activated carbons of Comparative Examples 1 and 2 , in which the ratio (B)/(A) was less than 1.6 or more than 7, had a small amount of 2-MIB adsorption.
この結果から、メソ孔の細孔容積（ＢＪＨ細孔容積（Ａ））に対するミクロ孔の総細孔容積（ＤＦＴ総細孔容積（Ｂ））の比率が所定の範囲内にある活性炭は、活性炭としての機能を損なうことなく、フミン酸等のフミン質共存下においても良好に２－ＭＩＢを吸着することができることが分かる。 These results show that activated carbon having a ratio of the total micropore volume (DFT total pore volume ( B )) to the mesopore pore volume ( BJH pore volume ( A )) within a specified range can effectively adsorb 2-MIB even in the presence of humic substances such as humic acid without impairing its function as activated carbon.
本発明によれば、フミン質共存下においても２－ＭＩＢ等のカビ臭原因物質を良好に吸着することができる活性炭を提供することができる。従って、このような活性炭、特に粉末状の活性炭は、浄水処理施設の原水に投入または供給等を行うことによってカビ臭を良好に抑制することができるため、有用である。 According to the present invention, it is possible to provide activated carbon that can effectively adsorb moldy odor-causing substances such as 2-MIB even in the presence of humic substances. Therefore, such activated carbon, particularly powdered activated carbon, is useful because it can effectively suppress moldy odors by being added or supplied to raw water at a water purification facility.
Claims (7)
前記細孔容積（Ａ）は、細孔直径２ｎｍ以上５０ｎｍ以下の範囲の細孔の細孔容積であり、
前記総細孔容積（Ｂ）は、細孔直径２ｎｍ未満の細孔の総細孔容積であり、
平均粒子径が２０μｍ以下の粉末状の活性炭である、活性炭。 the ratio (B)/(A) of the total pore volume (B) calculated from the carbon dioxide adsorption isotherm by DFT analysis to the pore volume (A) calculated from the nitrogen adsorption isotherm by the BJH method is 1.6 or more and 7.0 or less;
The pore volume (A) is the pore volume of pores having a pore diameter in the range of 2 nm to 50 nm,
The total pore volume (B) is the total pore volume of pores having a pore diameter of less than 2 nm;
Activated carbon is a powdered activated carbon having an average particle size of 20 μm or less .
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